不同浓度Cu掺杂AlN的电子结构和光学性质研究

采用基于密度泛函理论的平面波超软赝势和广义梯度近似的第一性原理计算方法,对理想纤锌矿AlN及不同浓度的Cu掺AlN的超晶胞结构进行了几何优化,计算并分析了它们的电子结构、磁电性质和光学性质.结果表明,掺杂后Cu3d态电子与其近邻的N2p态电子发生杂化,在带隙中引入杂质带,6.25%和12.5%的Cu掺杂体系表现出半金属铁磁性,体系总磁矩分别为2.56μв和2.42μв,25%的Cu掺杂体系表现出金属性.随着Cu浓度的增加,体系铁磁性反而减弱.Cu掺杂后体系介电函数虚部和复折射率函数在低能区发生明显变化,增强了体系对低频电磁波的吸收.当Cu浓度增加时体系对高频电磁波的吸收也随之加强.

Study on the Electronic Structures and Optical Properties of AlN with Different Concentrations of Cu Doping

The geometrical structures with different concentrations of Cu doped AlN were optimized by using the first principle density functional theory based on the full potential linearized augumented plane wave method. The electronic structures, magnetic and optical properties were calculated and discussed in detail. The results show that with the increasing of Cu doping concentrations, the hybridization of Cu3d and its neighboring N2p electrons weakens gradually and the system changes from a half ferromagnetic metal with direct band gap to a metal with indirect band gap. Simultaneously, magnetic moments of the system weakened and finally disappear. The imaginary part of dielectric functions and complex refractive index functions in the low energy region changes obviously with Cu doping. The absorption of low and high frequency electromagnetic waves are both enhanced with the increasing concentrations of Cu.